1. Field of the Invention
This invention relates generally to heat exchangers and more particularly is directed towards a new and improved heat exchanger for use in an extracorporeal blood handling system such as a blood oxygenator, or the like.
2. Description of the Prior Art
In many major surgical operations, particularly those involving open-heart surgery, it is the practice to connect the patient to a life support system by means of which the patient's blood is oxygenated artificially in an extracorporeal blood circuit and returned. During the course of the operation, control over the blood temperature is of great importance. In some instances it is desirable to maintain the blood at normal body temperature whereas in other instances it is desirable to chill the blood, particularly during coronary perfusion. Heat exchangers heretofore available for controlling blood temperature have not been satisfactory for a number of reasons, one of which is the poor control over the blood flow through the exchanger which prevents uniform thermal transfer. Typical prior art heat exchangers do not guide the blood into a controlled path or define a positive route for the blood, with the result that some of the blood flowing through the heat exchanger tends to follow a high flow route while other portions of the blood tend to be trapped in low flow zones or dead spots. Such a condition results in non-uniform thermal transfer so that all of the blood is not uniformly heated or cooled.
Accordingly, it is an object of the present invention to provide improvements in heat exchangers for extracorporeal blood handling systems. Another object of this invention is to provide a blood heat exchanger of high efficiency, long flow path and compact size. Still another object of this invention is to provide a simple, positive acting and highly efficient heat exchanger for extracorporeal blood circuits, which, in addition to providing heat exchanging functions, may also serve as a venous reservoir, a filter, an oxygenator, as well as a cardiotomy reservoir.